is this gltich or a lie?

when you block someone in whatsapp, in the chat the pharse" you blocked this contact" appear and when you unblock it says" you unblocked this contact", so when i checked my ex phone i found out that the boy i told her to block in whatsapp has a lot of "you unblocked this contact"

she says that it is the app fault and that she never unblocked him but i don't belleive her, so is this problem really possible in whatsapp or is she lying?